判断物体是否在视角内

public var isRendering:boolean=false;
private var lastTime:float=0;
private var curtTime:float=0;


function Update()
{
isRendering=curtTime!=lastTime?true:false;
lastTime=curtTime;
}

//如果物体可见，每个相机都会调用OnWillRenderObject。

//http://game.ceeger.com/Script/Camera/Camera.OnWillRenderObject.html
function OnWillRenderObject()
{
curtTime=Time.time;
}